Mark Williams cannot be caught at the top of the world rankings - according to his leading green baize rivals.

Williams, the reigning world, UK and Masters champion, started the new season by winning the LG Cup in Preston last month.

The Welsh left-hander starts his bid to add the British Open crown to his bulging trophy cabinet at the Brighton Centre tonight against Nottingham's Michael Holt.

Williams starts the tournament with a commanding lead of over 7,000 points in the rankings and has not lost his first round in a ranking event since the Scottish Open in February 1998 - a total of 47 tournaments.

This rock solid consistency has prompted his main challengers to write off their chances of overtaking him.

Stephen Hendry, who beat Dominic Dale 5-2 yesterday to book his place in the last 16, believes the race is over already.

"Mark is miles ahead of everyone so the No 1 spot is not going to be an issue this season," Hendry said. "He does not lose in the first round so he will only be stopped if he breaks both his arms."

John Higgins, beaten 9-5 by Williams in the LG Cup final and his nearest challenger in the rankings, agrees with Hendry's assessment.

"Mark is the man to beat at the moment," the world No 4 said.

"I think it is going to be impossible for anyone to catch him because we would need him to lose a few first round matches and he has not lost one for over five years. It would also need one of us to come out of the pack with a succession of wins, which is unlikely."

Williams, who drubbed Hendry 9-2 to win the British Open title in 1997, now lies joint third with Higgins on the all-time list of ranking tournament winners with 15 titles to his name, compared to Hendry's 34.

Steve Davis is second on the list with 28 titles and the 46-year-old will also be in action today.

Davis, back in the elite top 16 after a three-year gap, faces Northern Ireland's Joe Swail.